Nitrous oxide emissions from a commercial cornfield (&lt;i&gt;Zea mays&lt;/i&gt;) measured using the eddy-covariance technique

Abstract. Increases in observed atmospheric concentrations of the long-lived greenhouse gas, nitrous oxide (N2O), have been well documented. However, information on event-related instantaneous emissions during fertilizer applications is lacking. With the development of fast-response N2O analyzers, the eddy covariance (EC) technique can be used to gather instantaneous measurements of N2O concentrations to quantify the exchange of nitrogen between the soil and atmosphere. The objectives of this study were to evaluate the performance of a new EC system, to measure the N2O flux with the system, and finally to examine relationships of the N2O flux with soil temperature, soil moisture, precipitation, and fertilization events. We assembled an EC system that included a sonic anemometer and a fast-response N2O analyzer (quantum cascade laser spectrometer) in a cornfield in Nolensville, Tennessee during the 2012 corn growing season (4 April–8 August). Fertilizer amounts totaling 217 kg N ha−1 were applied to the experimental site. The precision of the instrument was 0.066 ppbv for 10 Hz measurements. The seasonal mean detection limit of the N2O flux measurements was 2.10 ng N m−2 s−1. This EC system can be used to provide reliable N2O flux measurements. The cumulative emitted N2O for the entire growing season was 6.87 kg N2O-N ha−1. The 30 min average N2O emissions ranged from 0 to 11 100 μg N2O{-}N m−2 h−1 (mean = 257.5, standard deviation = 817.7). Average daytime emissions were much higher than night emissions (278.8 ± 865.8 vs. 100.0 ± 210.0 μg N2O-N m−2 h−1). Seasonal fluxes were highly dependent on soil moisture rather than soil temperature, although the diurnal flux was positively related to soil temperature. This study was one of the few experiments that continuously measured instantaneous, high-frequency N2O emissions in crop fields over a growing season of more than 100 days.

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Nitrous oxide emissions from a commercial cornfield (Zea mays) measured using the eddy covariance technique

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-12839-2014 ◽

2014 ◽

Vol 14 (23) ◽

pp. 12839-12854 ◽

Cited By ~ 11

Author(s):

H. Huang ◽

J. Wang ◽

D. Hui ◽

D. R. Miller ◽

S. Bhattarai ◽

...

Keyword(s):

Nitrous Oxide ◽

Soil Moisture ◽

Soil Temperature ◽

Eddy Covariance ◽

Sonic Anemometer ◽

Growing Season ◽

Fast Response ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

N2o Flux

Abstract. Increases in observed atmospheric concentrations of the long-lived greenhouse gas nitrous oxide (N2O) have been well documented. However, information on event-related instantaneous emissions during fertilizer applications is lacking. With the development of fast-response N2O analyzers, the eddy covariance (EC) technique can be used to gather instantaneous measurements of N2O concentrations to quantify the exchange of nitrogen between the soil and atmosphere. The objectives of this study were to evaluate the performance of a new EC system, to measure the N2O flux with the system, and finally to examine relationships of the N2O flux with soil temperature, soil moisture, precipitation, and fertilization events. An EC system was assembled with a sonic anemometer and a fast-response N2O analyzer (quantum cascade laser spectrometer) and applied in a cornfield in Nolensville, Tennessee during the 2012 corn growing season (4 April–8 August). Fertilizer amounts totaling 217 kg N ha−1 were applied to the experimental site. Results showed that this N2O EC system provided reliable N2O flux measurements. The cumulative emitted N2O amount for the entire growing season was 6.87 kg N2O-N ha−1. Seasonal fluxes were highly dependent on soil moisture rather than soil temperature. This study was one of the few experiments that continuously measured instantaneous, high-frequency N2O emissions in crop fields over a growing season of more than 100 days.

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Warming Increases Nitrous Oxide Emission from the Littoral Zone of Lake Poyang, China

Sustainability ◽

10.3390/su12145674 ◽

2020 ◽

Vol 12 (14) ◽

pp. 5674

Author(s):

Junxiang Cheng ◽

Ligang Xu ◽

Mingliang Jiang ◽

Jiahu Jiang ◽

Yanxue Xu

Keyword(s):

Nitrous Oxide ◽

Soil Moisture ◽

Littoral Zone ◽

Abiotic Factors ◽

Growing Season ◽

N2o Emission ◽

N2o Emissions ◽

N2o Flux ◽

Lake Poyang ◽

Littoral Wetlands

Littoral wetlands are globally important for sustainable development; however, they have recently been identified as critical hotspots of nitrous oxide (N2O) emissions. N2O flux from subtropical littoral wetlands remains unclear, especially under the current global warming environment. In the littoral zone of Lake Poyang, a simulated warming experiment was conducted to investigate N2O flux. Open-top chambers were used to raise temperature, and the static chamber-gas chromatograph method was used to measure N2O flux. Results showed that the littoral zone of Lake Poyang was an N2O source, with an average flux rate of 8.9 μg N2O m−2 h−1. Warming significantly increased N2O emission (13.8 μg N2O m−2 h−1 under warming treatment) by 54% compared to the control treatment. N2O flux in the spring growing season was also significantly higher than that of the autumn growing season. In addition, temperature was not significantly related to N2O flux, while soil moisture only explained about 7% of N2O variation. These results imply that N2O emission experiences positive feedback effect on the ongoing warming of the climate, and abiotic factors (e.g., soil temperature and soil moisture) were not main controls on N2O variation in this littoral wetland.

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Nitrous Oxide Emissions in Pineapple Cultivation on a Tropical Peat Soil

Sustainability ◽

10.3390/su13094928 ◽

2021 ◽

Vol 13 (9) ◽

pp. 4928

Author(s):

Alicia Vanessa Jeffary ◽

Osumanu Haruna Ahmed ◽

Roland Kueh Jui Heng ◽

Liza Nuriati Lim Kim Choo ◽

Latifah Omar ◽

...

Keyword(s):

Nitrous Oxide ◽

Soil Temperature ◽

Peat Soil ◽

Farming Systems ◽

N2o Emission ◽

Nitrous Oxide Emissions ◽

Natural State ◽

N2o Emissions ◽

Wet Season ◽

Peat Soils

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.

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Quantifying nitrous oxide emissions from the foliage of cotton, maize and soybean crops

Crop and Pasture Science ◽

10.1071/cp14301 ◽

2015 ◽

Vol 66 (7) ◽

pp. 689 ◽

Cited By ~ 4

Author(s):

I. Rochester ◽

C. Wood ◽

B. Macdonald

Keyword(s):

Nitrous Oxide ◽

Zea Mays L ◽

Cropping Systems ◽

Time Of Day ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

N2o Flux ◽

Gossypium Hirsutum L ◽

Cotton Plants ◽

Glycine Max L

Nitrous oxide (N2O) is a potent greenhouse gas, contributing to global warming. Most of the N2O emitted from cropping systems is derived from the soil and is closely related to the use of nitrogen (N) fertiliser. However, several reports have shown that small, yet significant, portions of the N2O flux from cropping systems are emitted from the crop foliage. This research aimed to quantify N2O emissions from the foliage of field-grown cotton (Gossypium hirsutum L.), and included maize (Zea mays L.) and soybean (Glycine max L.) for comparison. We also aimed to identify differences in the timing of N2O emissions from foliage during the day and over an irrigation cycle. Individual plants were isolated from the soil, and the atmosphere surrounding the encapsulated plants was sampled over a 30-min period. Subplots that were previously fertilised with urea at 0, 80, 160, 240 and 320 kg N ha–1 and then sown to cotton were used to measure N2O flux from plants on three occasions. N2O flux from cotton foliage was also measured on five occasions during an 11-day irrigation cycle and at five times throughout one day. N2O flux from foliage accounted for a small but significant portion (13–17%) of the soil–crop N2O flux. N2O flux from foliage varied with plant species, and the time of day the flux was measured. N2O flux from cotton plants was closely related to soil water content. Importantly, the application of N fertiliser was not related to the N2O flux from cotton plants. The most plausible explanation of our results is that a proportion of the N2O that was evolved in the soil was transported through the plant via evapotranspiration, rather than being evolved within the plant. Studies that exclude N2O emissions from crop foliage will significantly underestimate the N2O flux from the system.

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Nitrous oxide emissions from the Arabian Sea: A synthesis

Atmospheric Chemistry and Physics ◽

10.5194/acp-1-61-2001 ◽

2001 ◽

Vol 1 (1) ◽

pp. 61-71 ◽

Cited By ~ 54

Author(s):

H. W. Bange ◽

M. O. Andreae ◽

S. Lal ◽

C. S. Law ◽

S. W. A. Naqvi ◽

...

Keyword(s):

Nitrous Oxide ◽

Arabian Sea ◽

Sea Surface ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

Coastal Zones ◽

N2o Flux ◽

In Situ Data ◽

Data Coverage

Abstract. We computed high-resolution (1º latitude x 1º longitude) seasonal and annual nitrous oxide (N2O) concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997. N2O concentrations are highest during the southwest (SW) monsoon along the southern Indian continental shelf. Annual emissions range from 0.33 to 0.70 Tg N2O and are dominated by fluxes from coastal regions during the SW and northeast monsoons. Our revised estimate for the annual N2O flux from the Arabian Sea is much more tightly constrained than the previous consensus derived using averaged in-situ data from a smaller number of studies. However, the tendency to focus on measurements in locally restricted features in combination with insufficient seasonal data coverage leads to considerable uncertainties of the concentration fields and thus in the flux estimates, especially in the coastal zones of the northern and eastern Arabian Sea. The overall mean relative error of the annual N2O emissions from the Arabian Sea was estimated to be at least 65%.

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Nitrous Oxide Emissions from an Alpine Grassland as Affected by Nitrogen Addition

Atmosphere ◽

10.3390/atmos12080976 ◽

2021 ◽

Vol 12 (8) ◽

pp. 976

Author(s):

Yufeng Wu ◽

Xiaopeng Gao ◽

Dengchao Cao ◽

Lei Li ◽

Xiangyi Li ◽

...

Keyword(s):

Growing Season ◽

Alpine Grassland ◽

Northwestern China ◽

Nitrous Oxide Emissions ◽

Heavy Rainfall Event ◽

N2o Emissions ◽

Flux Rate ◽

N Addition ◽

N2o Flux ◽

Growing Seasons

Nitrogen (N) addition is an important nutrient strategy for alpine grassland in northwestern China to improve productivity for livestock needs. A field experiment was conducted in a semi-arid alpine grassland in northwestern China to investigate the effect of N addition rates on soil N2O emissions over the growing seasons of 2017 and 2018. Treatments included six N addition rates (0, 10, 30, 60, 120, 240 kg N ha−1 y−1), which were applied before each growing season. The N2O fluxes increased with N addition rates and showed different episodic changes between the two growing seasons. In 2017, the maximum N2O flux rate occurred within 2 weeks following N addition. In 2018, however, the maximum N2O flux rate occurred later in the growing season due to a heavy rainfall event. Growing season cumulative N2O emissions ranged between 0.32 and 1.11 kg N ha−1, and increased linearly with N addition rates. Increasing N addition rates over 60 kg N ha−1 yr−1 did not further increase plant above-ground biomass. The inter-annual variability of N2O flux suggests the importance of soil moisture in affecting N2O emissions. It is particularly important to avoid over-applying N nutrients beyond plant needs to reduce its negative effect on the environment while maintaining livestock productivity. The N2O flux rate increased with soil dissolved organic carbon (DOC) and soil pH. These results suggest the optimal N addition rate to the livestock grassland in this region should be 60 kg N ha−1 yr−1.

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Nitrous oxide emissions from a waterbody in the Nenjiang basin, China

Hydrology Research ◽

10.2166/nh.2012.060 ◽

2012 ◽

Vol 43 (6) ◽

pp. 862-869 ◽

Cited By ~ 4

Author(s):

Qiao-Qi Sun ◽

Charlotte Whitham ◽

Kun Shi ◽

Guo-Hai Yu ◽

Xiao-Wei Sun

Keyword(s):

Nitrous Oxide ◽

Ammonium Nitrogen ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

N2o Flux ◽

Significant Relationships ◽

P Fertilizer ◽

Main Barrier ◽

Agricultural Areas ◽

Closed Chambers

Using static, closed chambers and gas chromatography techniques, nitrous oxide (N2O) emissions have been monitored for 1 year (2009–2010) on an inland running waterbody downstream of the Nenjiang basin, China. During the freezing period, holes were dug in the ice in order to obtain nitrous oxide samples. Here, we have focused on water-air gas exchange and factors which might influence N2O emissions and flux. Initial results indicate: (1) N2O flux rates reach peak emission in January and the annual emissions of N2O were low, being estimated at 0.35 ± 0.20 μgm–2 h−1; significant seasonal differences only appeared between January and July; (2) N2O flux rates have strong regularity and ice has been the main barrier to nitrous oxide release during winter; (3) 24-hour monitoring revealed that N2O flux remained steady during 9:00–17:00; (4) N2O emissions have significant relationships with ammonium nitrogen and total phosphorus concentrations in water (r = 0.4467, p = 0.020 and r = 0.4793, p = 0.011, respectively). The N2O flux released from the waterbody is determined by the chemical concentrations in the water. Following these results, we suggest that moderate use of N and P fertilizer at intensive agricultural areas will be beneficial in decreasing greenhouse gas emissions from this waterbody.

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Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

Biogeosciences ◽

10.5194/bg-2-377-2005 ◽

2005 ◽

Vol 2 (4) ◽

pp. 377-387 ◽

Cited By ~ 49

Author(s):

M. Pihlatie ◽

J. Rinne ◽

P. Ambus ◽

K. Pilegaard ◽

J. R. Dorsey ◽

...

Keyword(s):

Nitrous Oxide ◽

Spatial Variability ◽

Eddy Covariance ◽

Temporal Variability ◽

Nitrous Oxide Emissions ◽

Small Scale ◽

N2o Emissions ◽

Ecosystem Level ◽

N2o Fluxes ◽

Trunk Space

Abstract. Spring time nitrous oxide (N2O) emissions from an old beech (Fagus sylvatica L.) forest were measured with eddy covariance (EC) and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameters. Mean N2O fluxes over the five week measurement period were 5.6±1.1, 10±1 and 16±11 μg N m−2 h−1 from EC, automatic chamber and manual chambers, respectively. High temporal variability characterized the EC fluxes in the trunk-space. To reduce this variability, resulting mostly from random uncertainty due to measuring fluxes close to the detection limit, we averaged the fluxes over one day periods. The variability in the chamber measurements was much smaller and dominated by high small scale spatial variability. The highest emissions measured by the EC method occurred during the first week of May when the trees were leafing and the soil moisture content was at its highest. If chamber techniques are used to estimate ecosystem level N2O emissions from forest soils, placement of the chambers should be considered carefully to cover the spatial variability in the soil N2O emissions. The EC technique, applied in this study, is a promising alternative tool to measure ecosystem level N2O fluxes in forest ecosystems. To our knowledge, this is the first study to demonstrate that the EC technique can be used to measure N2O fluxes in the trunk-space of a forest.

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Effects of soil temperature and moisture on methane uptakes and nitrous oxide emissions across three different ecosystem types

Biogeosciences Discussions ◽

10.5194/bgd-10-927-2013 ◽

2013 ◽

Vol 10 (1) ◽

pp. 927-965 ◽

Cited By ~ 14

Author(s):

G. J. Luo ◽

R. Kiese ◽

B. Wolf ◽

K. Butterbach-Bahl

Keyword(s):

Nitrous Oxide ◽

Soil Moisture ◽

Soil Temperature ◽

Tropical Forest ◽

Environmental Conditions ◽

Temperate Forest ◽

Explanatory Power ◽

Nitrous Oxide Emissions ◽

Forest Site ◽

Methane Uptake

Abstract. In this paper, we investigate similarities of effects of soil environmental drivers on year-round daily soil fluxes of nitrous oxide and methane for three distinct semi-natural or natural ecosystems: temperate spruce forest, Germany; tropical rain forest, Queensland, Australia; and ungrazed semi-arid steppe, Inner Mongolia, China. Annual cumulative fluxes of nitrous oxide and methane varied markedly among ecosystems, with nitrous oxide fluxes being highest for the tropical forest site (tropical forest: 0.96 kg N ha−1yr−1; temperate forest: 0.67 kg N ha−1yr−1; steppe: 0.22 kg N ha−1yr−1), while rates of soil methane uptake were approximately equal for the temperate forest (3.45 kg C ha−1yr−1) and the steppe (3.39 kg C ha−1yr−1), but lower for the tropical forest site (2.38 kg C ha−1yr−1). In order to allow for cross-site comparison of effects of changes in soil moisture and soil temperature on fluxes of methane and nitrous oxide, we used a normalization approach. Data analysis with normalized data revealed that across sites, optimum rates of methane uptake are found at environmental conditions representing approximately average site environmental conditions. This might have rather important implications for understanding effects of climate change on soil methane uptake potential, since any shift in environmental conditions is likely to result in a reduction of soil methane uptake ability. For nitrous oxide, our analysis revealed expected patterns: highest nitrous oxide emissions under moist and warm conditions and large nitrous oxide fluxes if soils are exposed to freeze-thawing effects at sufficient high soil moisture contents. However, the explanatory power of relationships of soil moisture or soil temperature to nitrous oxide fluxes remained rather poor (≤ 0.36). When combined effects of changes in soil moisture and soil temperature were considered, the explanatory power of our empirical relationships with regard to temporal variations in nitrous oxide fluxes were at maximum about 50%. This indicates that other controlling factors such as N and C availability or microbial community dynamics might exert a significant control on the temporal dynamic of nitrous oxide fluxes. Though underlying microbial processes such as nitrification and denitrification are sensitive to changes in the environmental regulating factors, important regulating factors like moisture and temperature seem to have both synergistic and antagonistic effects on the status of other regulating factors. Thus we cannot expect a~simple relationship between them and the pattern in the rate of emissions, associated with denitrification or nitrification in the soils. In conclusion, we hypothesize that our approach of data generalization may prove beneficial for the development of environmental response models which can be used across sites, and which are needed to help better understanding climate change feedbacks on biospheric sinks or sources of nitrous oxide and methane.

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Winter grazing of forages - soil moisture and tillage methods impact nitrous oxide emissions and dry matter production

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2004.66.2571 ◽

2004 ◽

pp. 135-140

Author(s):

S.M. Thomas ◽

G.S. Francis ◽

H.E. Barlow ◽

M.H. Beare ◽

L.A. Trimmer ◽

...

Keyword(s):

Nitrous Oxide ◽

Soil Moisture ◽

Soil Compaction ◽

Dry Matter ◽

Field Capacity ◽

Significant Loss ◽

Nitrous Oxide Emissions ◽

N2o Emissions ◽

Forage Crops ◽

Matter Production

Grazing of winter forage crops can cause extensive compaction of soils that may reduce re-growth of crops and lead to large emissions of nitrous oxide (N2O). A field trial was undertaken to investigate the effects of cattle grazing at three soil moisture contents on N2O emissions and dry matter (DM) production of a winter forage crop established by intensive (IT), minimum (MT), or no tillage (NT) practices. A multi-grazing triticale (cv. Doubletake) was sown in the main tillage plots in March 2003. In June, the tillage plots (three replicates) were each divided into six split plots and additional treatments were imposed: simulated treading (+/-); soil moisture at treading (< field capacity (FC); FC; and >FC); and urine (+/-). Tillage practice and soil moisture content at treading affected soil compaction. The greatest increase in surface soil (0-7.5 cm) bulk density occurred in IT plots treaded at >FC. Treading wet soil greatly increased (up to 8 times) the amount of N2O emitted. The highest cumulative N2O emissions were from IT (14.9 kg N/ha) and MT (12.7 kg N/ha) urine-applied plots treaded at >FC. There was no difference in N2O emitted from treaded FC. Treading at FC also caused a significant loss of DM production in the IT plots but not in the MT plots. DM production in the NT plots was unaffected by treading. Establishing winter forage crops by direct drilling may be an important management option to mitigate N2O emissions and maintain high DM production of grazed forages, as will avoiding grazing when soils are wet. Keywords: forage crops, grazing, nitrous oxide, soil compaction, tillage, urine

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